Brightness in nighttime fireworks video fluctuating

[makneyse]

Hi All! I'm back with another fireworks video question. I had a very successful flight last year (on the 4th of July, here in the States) and went out last night to do it again. In a nutshell, I flew a waypoints mission multiple times in various stages of light. All my camera settings were in manual but the nighttime footage fluctuates like the camera was in auto. I don't notice it when I'm viewing the footage on my phone via DJI GO4 with the SD card in the drone but it's very noticeable when downloaded and viewed on a computer. BTW, I've tried multiple computers and different video players so I know it's not a monitor auto brightness or power saving thing. Here's a snipit of it:

fluctuating fireworks.mp4

drive.google.com

If you look at the city lights in the shot, they get dim and then brighten up pretty drastically.

The settings used in this clip:
4K, 60p
2.8
1/60
ISO 400
D-Cinelike -1,-1,-1
I'm flying a P4PV2.0

I know it's ideal to have a 1/120 shutter but I wanted to avoid an ISO of 800. I'm curious if this is the culprit...

I also went back to double check my camera settings and they're right where I left them. Nothing accidentally got switched to auto.

Thanks in advance for the help!

 

[Pygar70]

The video came through in 1080p, rather than 4K. What I see are grainy/smudgy patches of a slightly lighter shade, covering perhaps three quarters of the screen in total. These patches move and oscillate, causing a kind of flashing effect. At times these artifacts appear to obscure the street lights, something more noticeable in the far distance.
It doesn't seem to me that your camera settings are changing mid-flight. I think it's an image processing issue, but I don't have expertise in this area. Someone else?

 

[makneyse]

You are correct that I did export the clip in 1080 and it does look pretty low quality. Not sure if that's a Google Drive thing or just because I just did a quick and simple export. Those black artifacts don't appear in the original so I'll see if I can post a cleaner copy of the footage. But at least you can still see the fluctuations in the brightness. At first I thought it was bright fireworks causing the camera to compensate but upon further review, it looks like my camera settings remained in manual as I had set them.
If anyone else has any ideas as to why the lights are dimming and brightening back up, I'm all ears!

 

[makneyse]

I exported another snipit (at 1080 again) and posted it on YouTube instead of Google Drive. And it looks like you're right. There are dark, blocky patches all over the frame. It's like the camera or SD card or something couldn't handle all of the information. I'm using at SanDisk 32 GB Extreme Pro cards. I'm at a loss as to why this happened...

 

[roosta]

Is it only performing like this in dark scenes/night?

RoOSTA

 

[makneyse]

Is it only performing like this in dark scenes/night?

RoOSTA

This is the only time I've seen it happen. I did the same waypoints mission earlier in the evening before it was dark and it looked fine. But the three takes I did in the dark had this weird artifact thing going on.